Pyridinium ''p''-toluenesulfonate (PPTS) is a colourless solid

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

pyridine Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a ...

and ''p''-toluenesulfonic acid.

Uses

In organic synthesis, PPTS is used as a weakly acidic

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

, providing an organic soluble source of pyridinium (C₅H₅NH⁺) ions. For example, PPTS is used to deprotect

silyl ethers Silylation is the introduction of one or more (usually) substituted silyl groups (R3Si) to a molecule. The process is the basis of organosilicon chemistry. Of organic compounds Alcohols, carboxylic acids, amines, thiols, and phosphates can be sily ...

or tetrahydropyranyl ethers when a substrate is unstable to stronger acid catalysts. It is also a commonly used catalyst for the preparation of

acetal In organic chemistry, an acetal is a functional group with the connectivity . Here, the R groups can be organic fragments (a carbon atom, with arbitrary other atoms attached to that) or hydrogen, while the R' groups must be organic fragments n ...

s and

ketal In organic chemistry, an acetal is a functional group with the connectivity . Here, the R groups can be organic fragments (a carbon atom, with arbitrary other atoms attached to that) or hydrogen, while the R' groups must be organic fragments no ...

s from aldehydes and ketones.

References

{{Reflist Sulfonates Pyridinium compounds Salts Reagents for organic chemistry P-Tosyl compounds